As urban growth outstrips water supplies, how can the global challenge of providing water be met? Mixing history and policy analysis, Steven Erie tells the compelling story of the Metropolitan Water District of Southern California (MWD) -- one of the world's largest and most important public water agencies -- and its role in building the world's eighth largest economy in a semi-desert. Using untapped primary sources, the author reexamines this great regional experiment from its obscure 1920s-era origins, through the Colorado River Aqueduct and State Water Projects, to today's daunting mission of drought management, water quality, environmental stewardship, and post-9/11 supply security. A key focus is MWD's navigation of recent epic water battles: San Diego's combative quest for water independence.

WHAT THE CRITICS SAY:

"Erie's persuasive argument that the Metropolitan Water District is one of the creative but flawed designers of Southern California is haunted by forgetfulness: We forget where our water comes from.... We forget who manages it for us and why water policy is the most important political decision we never get to make."

"Dr. Erie, you are originally from California. A native." "I was born in Glendale and raised in Eagle Rock and Arcadia. The first half of my life was spent in L.A. But for a while I lived in Washington, D.C. I'm a refugee from the Reagan revolution."

"You're happy in California."

"I spent great weekends in New York City, Washington, Boston, Montreal. But listen, when I went to Albany, N.Y., and discovered winter wasn't optional, I couldn't get back to Southern California quick enough."

"I'm going to ask some simple questions. Who owns water? Is it a private resource?"

"There's a big debate about whether it's a public resource or a private commodity. That has been one of the big issues about the growth of water markets and water transfers. There are many who still see it as a public resource. But certainly rights to it, as property, have grown in the last 40 or 50 years."

"We've got six billion people on the planet now. You say [in the book], only three percent of the planet's water is drinkable. The rest is oceans."

"Yes, most of it is seawater -- salty. What we're thinking about doing here in San Diego, is desalination -- tap into the huge amount of water immediately to the west of us."

"Professor, has anyone estimated how many people that three percent -- that drinkable water -- can support? When do we reach critical mass?"

"I'm sure somebody has. I haven't. I'm just not a global person, I'm a regional person. I can talk knowledgeably about Southern California. And certainly I can tell you, we could not have a population of more than 750,000 living from Santa Barbara to San Diego without imported water."

"How many folks are there now residing in that arid area?"

"We're at about 18 million in Southern California."

"But you're saying local water sources alone could only support 750,000 people?

"Maybe a million, with conservation."

"How close," I ask, "are San Diegans to turning on their water taps and having nothing come out?"

"We're not there yet. We bought a little bit of time with this very controversial Imperial Valley deal, the cost of which has still not been fully estimated. Salt and sea restoration, lining of the canals and things like that [help too]."

"Yes," I interject, "could you explain the purpose of lining canals?"

"Well, when the All-American and Coachella Canals were constructed way back when, they were earthen. Water leaks out of them. Ironically, [this] seepage helped replenish the Salton Sea and it allowed the Mexicali farmers to grow crops. Lining involved sealing the porous surfaces of canals. It was intended as a conservation measure to limit water loss, but in the process we created real problems for the Salton Sea. Seepage is not replenishing it nor the Mexicali Valley farms on the Mexican side. It's the reason that they've been in court."

"How many water systems -- aqueducts, reservoirs -- are there supplying the Southern California region?"

"There are 7 Colorado River states in the south, and also 7 northern states. So 14 states are drawing from the river. Anyway, the Colorado River Aqueduct is one source, the State Water Project (passed by the voters in 1962) is a second, and then there are two Los Angeles City aqueducts, I and II. So there are roughly four sources of imported water coming into Southern California."

"Is there any one agency or body that governs it all?"

"If there is a [water] policymaker in the region, it's MWD [Metropolitan Water District of Southern California]. It was set up to provide a supplemental source of water for Los Angeles and all of its suburbs. It's municipal. MWD is a special district created by the state legislature. It started small. It included only L.A. and 12 of its suburbs back in 1928, and it started out as a water wholesaler. The retailers were the Department of Water and Power, and the Beverly Hills, Pasadena, and Glendale municipal water departments. Since then, its responsibilities have grown significantly. MWD now motivates member agencies and retail water-users with incentives like subsidies for conservation and for desalination projects."

"Is desalination a practical answer -- any kind of help at all?"

Dr. Erie pauses. "That's a complicated question. Gathering the water is still costly, and people don't realize that there are hidden costs to 'desal.' There's the treatment process, to make it drinkable. There are also the power costs, which are extremely high in many places, for pumping the water back up hill, because our whole water complex is a gravity flow system. The reservoirs are elevated, and you've got to pump the water upward to put it in those reservoirs. And there's been a big debate about the impact of the required power plants on the marine environment, and on the coast by the intake and discharge of seawater. These are very contentious issues. Environmentalists are trying to fight desalination, saying that we really ought to move toward better conservation [first], including desert landscaping. But I think there's a role for desal, particularly as [water] carrying capacity reaches its limits. By 2030 all of those aqueducts literally won't bring enough imported water into Southern California, so there's going to be growing pressure. The bottleneck we're facing in the next 20 years is that the conveyance system is only so big, and we're not going to make it any bigger."